On 02/28/2012 08:47 PM, Yehuda Sadeh Weinraub wrote:
On Tue, Feb 28, 2012 at 7:21 PM, Alex Elder<elder@xxxxxxxxxxxxx> wrote:
All names defined in the directory and file virtual extended
attribute tables are constant, and the size of each is known at
compile time. So there's no need to compute their length every
time any file's attribute is listed.
Record the length of each string and use it when needed to determine
the space need to represent them. In addition, compute the
aggregate size of strings in each table just once at initialization
time.
Signed-off-by: Alex Elder<elder@xxxxxxxxxxxxx>
---
fs/ceph/super.c | 3 ++
fs/ceph/super.h | 2 +
fs/ceph/xattr.c | 56
++++++++++++++++++++++++++++++++++++++++++++++++++----
3 files changed, 56 insertions(+), 5 deletions(-)
. . .
@@ -87,6 +88,7 @@ static size_t ceph_vxattrcb_dir_rctime(struct
ceph_inode_info *ci, char *val,
#define XATTR_NAME_CEPH(_type, _name) \
{ \
.name = CEPH_XATTR_NAME(_type, _name), \
+ .name_size = sizeof CEPH_XATTR_NAME(_type, _name), \
You should use sizeof(x) instead of sizeof x.
I got the same comment when I tried using this form on XFS code.
I personally prefer this form--it tells you that "x" in this case
is an object, not a type.
However I will fix all references to "sizeof object" to use
sizeof(object) instead--here and in the future.
-Alex
.getxattr_cb = ceph_vxattrcb_ ## _type ## _ ## _name,
\
.readonly = true, \
}
@@ -102,6 +104,7 @@ static struct ceph_vxattr ceph_dir_vxattrs[] = {
XATTR_NAME_CEPH(dir, rctime),
{ 0 } /* Required table terminator */
};
+static size_t ceph_dir_vxattrs_name_size; /* total size of all names
*/
/* files */
@@ -127,11 +130,13 @@ static struct ceph_vxattr ceph_file_vxattrs[] = {
/* The following extended attribute name is deprecated */
{
.name = XATTR_CEPH_PREFIX "layout",
+ .name_size = sizeof XATTR_CEPH_PREFIX "layout",
here too.
.getxattr_cb = ceph_vxattrcb_file_layout,
.readonly = true,
},
{ 0 } /* Required table terminator */
};
+static size_t ceph_file_vxattrs_name_size; /* total size of all names
*/
static struct ceph_vxattr *ceph_inode_vxattrs(struct inode *inode)
{
@@ -142,6 +147,46 @@ static struct ceph_vxattr *ceph_inode_vxattrs(struct
inode *inode)
return NULL;
}
+static size_t ceph_vxattrs_name_size(struct ceph_vxattr *vxattrs)
+{
+ if (vxattrs == ceph_dir_vxattrs)
+ return ceph_dir_vxattrs_name_size;
+ if (vxattrs == ceph_file_vxattrs)
+ return ceph_file_vxattrs_name_size;
+ BUG();
+
+ return 0;
+}
+
+/*
+ * Compute the aggregate size (including terminating '\0') of all
+ * virtual extended attribute names in the given vxattr table.
+ */
+static size_t __init vxattrs_name_size(struct ceph_vxattr *vxattrs)
+{sizeof
+ struct ceph_vxattr *vxattr;
+ size_t size = 0;
+
+ for (vxattr = vxattrs; vxattr->name; vxattr++)
+ size += vxattr->name_size;
+
+ return size;
+}
+
+/* Routines called at initialization and exit time */
+
+void __init ceph_xattr_init(void)
+{
+ ceph_dir_vxattrs_name_size = vxattrs_name_size(ceph_dir_vxattrs);
+ ceph_file_vxattrs_name_size = vxattrs_name_size(ceph_file_vxattrs);
+}
+
+void ceph_xattr_exit(void)
+{
+ ceph_dir_vxattrs_name_size = 0;
+ ceph_file_vxattrs_name_size = 0;
+}
+
static struct ceph_vxattr *ceph_match_vxattr(struct inode *inode,
const char *name)
{
@@ -614,11 +659,12 @@ ssize_t ceph_listxattr(struct dentry *dentry, char
*names, size_t size)
goto out;
list_xattr:
- vir_namelen = 0;
- /* include virtual dir xattrs */
- if (vxattrs)
- for (i = 0; vxattrs[i].name; i++)
- vir_namelen += strlen(vxattrs[i].name) + 1;
+ /*
+ * Start with virtual dir xattr names (if any) (including
+ * terminating '\0' characters for each).
+ */
+ vir_namelen = ceph_vxattrs_name_size(vxattrs);
+
/* adding 1 byte per each variable due to the null termination */
namelen = vir_namelen + ci->i_xattrs.names_size + ci->i_xattrs.count;
err = -ERANGE;
--
1.7.5.4
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